Three dimensional images (3D) are increasingly used to display vivid images in movies, electronic games and in other applications. For example 3D movies are displayed in theatres and are viewed by persons equipped with special 3D glasses. Additionally, 3D movies and electronic games may be displayed on specially equipped televisions or computer displays for viewing by persons equipped with special 3D glasses.
The basic approach to displaying 3D images is to display two slightly offset images separately to the left and right eye. The two principal strategies have been used to accomplish this are: (1) for the viewer to wear a special 3D eyepiece that filters each offset image to a different eye; and (2) to split the light source directionally into each of the viewer's eyes, thus eliminating the need for special glasses.
One increasingly common approach to projecting stereoscopic image pairs is a head mounted display system that mounts to a person's head and that displays a virtual image on an attached eyepiece. Head mounted displays are often used in simulators or for games, though they can also be used to view media such as movies or digital photos.
A portable or mobile electronics device, referred to hereinbelow as a mobile device, such as a smartphone, is capable of generating and displaying a stereoscopic or 3D movie or image that when projected onto an eyepiece appears to a viewer to have depth, i.e. three dimensions. This approach offers a low cost, mobile, solution to viewing 3D images since mobile electronics devices such as smartphones are widespread and relatively inexpensive. Therefore, it would be desirable to able to attach a mobile device to a head mounted display that properly displays 3D images or movies on an attached eyepiece.
Such a device could also be used to view traditional, 2D media, including images, photos and web content in the form of a virtual display in front of the viewer. This would be desirable because of the relative size and comfortable position of the virtual display as compared to a laptop or small screen device.
Prior art head mounted displays typically mount over a person's face in such a way that facial features are not visible. Thus, when a person is speaking to or looking at another person wearing a prior art head mounted display they are unable to see the person's face. The lack of visual cues provided by facial features makes such human interactions somewhat unnatural.
Therefore it would be advantageous if the front portion of a head mounted display would rest above the eyebrows leaving the face of the person wearing the device substantially unobstructed so that a person looking at someone wearing such a device could see his/her facial features.
Another disadvantage of prior art head mounted displays is that they support a fairly narrow range of interpupilary distances. Thus it would be advantageous to provide a head mounted display that accommodated a wide range of interpupilary distances.